Skip mixed mode tests when tokens not provided (#9213)

* Skip when tokens not provided

* Add explanation

Author: penalosa

fixtures/mixed-mode-node-test/tests/startMixedModeSession.test.js

@@ -6,7 +6,16 @@ import { experimental_startMixedModeSession } from "wrangler";
 process.env.CLOUDFLARE_ACCOUNT_ID = process.env.TEST_CLOUDFLARE_ACCOUNT_ID;
 process.env.CLOUDFLARE_API_TOKEN = process.env.TEST_CLOUDFLARE_API_TOKEN;
 
-describe("startMixedModeSession", () => {
+// Mixed Mode relies on deploying a Worker to a user's account, and so the following tests require authentication
+// This is provided in CI, but forks of the repo/running the fixture tests locally won't necessarily have authentication
+// As such, we skip the tests if authentication isn't provided.
+const baseDescribe =
+	process.env.TEST_CLOUDFLARE_ACCOUNT_ID &&
+	process.env.TEST_CLOUDFLARE_API_TOKEN
+		? describe
+		: describe.skip;
+
+baseDescribe("startMixedModeSession", () => {
 	test("simple AI request to the proxyServerWorker", async () => {
 		const mixedModeSession = await experimental_startMixedModeSession({
 			AI: {